


SI Prefixes Table
Example: 1 TW=1000 GW (W=Watt)
  
    | Symbol | Prefix | Factor | 
  
    | Y | Yotta | 1024 | 
  
    | Z | Zetta | 1021 | 
  
    | E | Exa | 1018 | 
  
    | P | peta | 1015 | 
  
    | T | tera | 1012 | 
  
    | G | giga | 109 | 
  
    | M | Mega | 106 | 
  
    | k | kilo | 103 | 
  
    | h | hecto | 102 | 
  
    | da | deca | 101 | 
  
    | d | deci | 10-1 | 
  
    | c | centi | 10-2 | 
  
    | m | milli | 10-3 | 
  
    | µ u | micro | 10-6 | 
  
    | n | nano | 10-9 | 
  
    | p | pico | 10-12 | 
  
    | f | femto | 10-15 | 
  
    | a | atto | 10-18 | 
  
    | z | zepto | 10-21 | 
  
    | y | yokto | 10-24 | 
    Note: In the computer world things are a bit different:
  
    | Symbol | Prefix | Factor | Factor | 
  
    | P | peta | 250 | 1125899906842624 | 
  
    | T | tera | 240 | 1099511627776 | 
  
    | G | giga | 230 | 1073741824 | 
  
    | M | Mega | 220 | 1048576 | 
  
    | k | kilo | 210 | 1024 | 
There is also the prefixes adopted by IEC in order to cope with the digital world. These are not widely used (yet).
  
    | Symbol | Prefix | Factor | Factor | 
  
    | Ei | exbi | 260 | 1152921504606846976 | 
  
    | Pi | pebi | 250 | 1125899906842624 | 
  
    | Ti | tebi | 240 | 1099511627776 | 
  
    | Gi | gibi | 230 | 1073741824 | 
  
    | Mi | mebi | 220 | 1048576 | 
  
    | Ki | kibi | 210 | 1024 | 
  
    | Source: | Farnell Components Catalogue | 
  Copyright © The Hardware Book Team 1996-2004.
  May be copied and redistributed, partially or in whole, as appropriate.
  Document last modified: 2002-01-13